It's very difficult for me to understand which state the play length toggle icon is at. Looking at the icon doesn't give the editor any indication about which state the button is in.

I would like the icon to light up or something to tell me that MC has preloaded one minute ahead, not the whole timeline. 

It would be good if the icon would highlight like this when it is enabled:

Drag it to your record monitor and place it where your normal play button is and when you click it it will highlight white when it is activated. 

Andi